Collect. Czech. Chem. Commun. 1981, 46, 31-39

Theoretical study of electron structure and stability of quasiaromatic analogues of azulene

Pavol Zahradník, Elena Ďurčíková and Jaroslav Leška

Department of Organic Chemistry, Comenius University, 816 31 Bratislava


Semiempirical CNDO/2 method was used in the study of 23 quasiaromatic azulene analogues containing a hydrogen bridge A..H-D, where A and D denote O, NH, or S. The values of the stabilization energy, interaction energy, and changes of Wiberg's indexes suggest that the stability of the studied compounds is caused by a strong hydrogen bond as well as by a strong delocalization of the π-electron system. Derivatives in which A and D are O and NH are especially stable. Derivatives containing an oxo or thio group are preferred in tautomeric equilibriums.